GM Service Manual Online
For 1990-2009 cars only

The windshield wiper/washer system consists of the following components:

    • wiper motor and transmission module
    • wiper arm and blade assemblies
    • washer pump
    • washer solvent container
    • wiper/washer switch

The wiper/washer system operates in the following modes:

    • WASH
    • MIST
    • DELAY
    • LO
    • HI

When the wiper switch is turned OFF, the wiper motor returns the wipers to the park position.

Voltage is applied to the accessory voltage circuit when the ignition is in the ACCY or ON position.

The wiper motor is equipped with radio frequency interference (RFI) suppression.

Wash Operation

In the WASH mode, voltage is applied to the following circuits:

    • windshield wiper switch on signal
    • windshield washer pump control

The windshield washer pump sprays washer solvent onto the windshield. The windshield wipers operate at low or high speed for 3-5 wipes and return to the park position. If the wipers are in DELAY, LO, or HI mode, they return to that operation after the wash cycle.

Mist Operation

In the MIST mode, voltage is applied to the following circuits:

    • windshield wiper switch on signal
    • windshield wiper switch low/pulse signal

The wipers make one sweep at low speed and return to the park position. If the wiper switch is held in MIST mode, the wipers will continue to operate until the switch is released.

Delay Operation

In the DELAY mode, voltage is applied to the following circuits:

    • windshield wiper switch on signal
    • windshield wiper switch low/pulse signal

The wipers make single sweeps with a time interval between sweeps. The time interval is controlled by the wiper motor cover, based on the voltage sent through the variable resistor in the wiper/washer switch.

Lo Operation

In the LO mode, voltage is applied to the following circuits:

    • windshield wiper switch on signal
    • windshield wiper switch low/pulse signal

The wiper motor runs continuously at low-speed.

Hi Operation

In the HI mode, voltage is applied to the following circuits:

    • windshield wiper switch on signal
    • windshield wiper switch low/pulse signal
    • windshield wiper switch high speed

The wiper motor runs continuously at high-speed.

Park Position Operation

When turned OFF from any position, the wipers complete the last sweep and park. When the wiper switch is turned OFF, battery voltage continues to be applied to the accessory voltage circuit. The wiper motor continues to run until the internal motor park switch opens.